Java冒泡排序法

public class Sort {
    public void BubbleSort(int[] arr){
        for(int i = 0;i<arr.length-1;i++) {
            for (int j = 1; j < arr.length; j++) {
                if (arr[j - 1] > arr[j]) {
                    int tmp = arr[j - 1];
                    arr[j - 1] = arr[j];
                    arr[j] = tmp;
                }
            }
        }
        System.out.println(Arrays.toString(arr));
    }
    public static void main(String[] args){
        Sort sort = new Sort();
        int[]arr1={7,4,1,2};
        sort.BubbleSort(arr1);
    }
}